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* [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed
@ 2020-06-09 18:51 lewissbaker.opensource at gmail dot com
2020-06-09 19:00 ` [Bug c++/95616] " iains at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: lewissbaker.opensource at gmail dot com @ 2020-06-09 18:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95616
Bug ID: 95616
Summary: [coroutines] coroutines with potentially-throwing
'co_await promise.final_suspend()' expressions should
be ill-formed
Product: gcc
Version: 10.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: lewissbaker.opensource at gmail dot com
Target Milestone: ---
The wording of [dcl.fct.def.coroutine]/15 states:
> The expression co_await promise.final_suspend() shall not be potentially-throwing ([except.spec]).
See http://eel.is/c++draft/dcl.fct.def.coroutine#15
and http://eel.is/c++draft/except.spec#6
I believe this means that the compiler should reject with a diagnostic any
coroutine with a promise_type where `co_await promise.final_suspend()` is not
noexcept. ie. all of the following must be declared noexcept (if they form part
of the await-expression):
- promise_type::final_suspend()
- finalSuspendObj.operator co_await()
- finalSuspendAwaiter.await_ready()
- finalSuspendAwaiter.await_suspend()
- finalSuspendAwaiter.await_resume()
- finalSuspedObj destructor
- finalSuspendAwaiter destructor
GCC (and Clang) currently accepts code that that does not declare
final_suspend() as
noexcept.
e.g. see https://godbolt.org/z/Et_5eo
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/95616] [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed
2020-06-09 18:51 [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed lewissbaker.opensource at gmail dot com
@ 2020-06-09 19:00 ` iains at gcc dot gnu.org
2020-07-23 6:52 ` rguenth at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: iains at gcc dot gnu.org @ 2020-06-09 19:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95616
Iain Sandoe <iains at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2020-06-09
Keywords| |accepts-invalid
Target Milestone|--- |10.2
Assignee|unassigned at gcc dot gnu.org |iains at gcc dot gnu.org
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Iain Sandoe <iains at gcc dot gnu.org> ---
thanks for the report
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/95616] [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed
2020-06-09 18:51 [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed lewissbaker.opensource at gmail dot com
2020-06-09 19:00 ` [Bug c++/95616] " iains at gcc dot gnu.org
@ 2020-07-23 6:52 ` rguenth at gcc dot gnu.org
2021-02-16 9:19 ` iains at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-07-23 6:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95616
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|10.2 |10.3
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10.2 is released, adjusting target milestone.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/95616] [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed
2020-06-09 18:51 [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed lewissbaker.opensource at gmail dot com
2020-06-09 19:00 ` [Bug c++/95616] " iains at gcc dot gnu.org
2020-07-23 6:52 ` rguenth at gcc dot gnu.org
@ 2021-02-16 9:19 ` iains at gcc dot gnu.org
2021-03-05 16:59 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: iains at gcc dot gnu.org @ 2021-02-16 9:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95616
--- Comment #3 from Iain Sandoe <iains at gcc dot gnu.org> ---
Created attachment 50197
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50197&action=edit
Patch being tested
this fixes the top-level check, but doesn't yet look at (a) operator co_await
(b) the await_* functions.
needs some tidying up.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/95616] [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed
2020-06-09 18:51 [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed lewissbaker.opensource at gmail dot com
` (2 preceding siblings ...)
2021-02-16 9:19 ` iains at gcc dot gnu.org
@ 2021-03-05 16:59 ` cvs-commit at gcc dot gnu.org
2021-03-22 22:04 ` cvs-commit at gcc dot gnu.org
2021-03-24 12:45 ` iains at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-03-05 16:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95616
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Iain D Sandoe <iains@gcc.gnu.org>:
https://gcc.gnu.org/g:9ee91079fd5879cba046e452ab5593372166b2ab
commit r11-7528-g9ee91079fd5879cba046e452ab5593372166b2ab
Author: Iain Sandoe <iain@sandoe.co.uk>
Date: Mon Feb 15 17:11:31 2021 +0000
coroutines : Do not accept throwing final await expressions [PR95616].
From the PR:
The wording of [dcl.fct.def.coroutine]/15 states:
* The expression co_await promise.final_suspend() shall not be
potentially-throwing ([except.spec]).
See http://eel.is/c++draft/dcl.fct.def.coroutine#15
and http://eel.is/c++draft/except.spec#6
ie. all of the following must be declared noexcept (if they form part of
the await-expression):
- promise_type::final_suspend()
- finalSuspendObj.operator co_await()
- finalSuspendAwaiter.await_ready()
- finalSuspendAwaiter.await_suspend()
- finalSuspendAwaiter.await_resume()
- finalSuspedObj destructor
- finalSuspendAwaiter destructor
This implements the checks for these cases and rejects such code with
a diagnostic if exceptions are enabled.
gcc/cp/ChangeLog:
PR c++/95616
* coroutines.cc (coro_diagnose_throwing_fn): New helper.
(coro_diagnose_throwing_final_aw_expr): New helper.
(build_co_await): Diagnose throwing final await expression
components.
(build_init_or_final_await): Diagnose a throwing promise
final_suspend() call.
gcc/testsuite/ChangeLog:
PR c++/95616
* g++.dg/coroutines/pr95616-0-no-exceptions.C: New test.
* g++.dg/coroutines/pr95616-0.C: New test.
* g++.dg/coroutines/pr95616-1-no-exceptions.C: New test.
* g++.dg/coroutines/pr95616-1.C: New test.
* g++.dg/coroutines/pr95616-2.C: New test.
* g++.dg/coroutines/pr95616-3-no-exceptions.C: New test.
* g++.dg/coroutines/pr95616-3.C: New test.
* g++.dg/coroutines/pr95616-4.C: New test.
* g++.dg/coroutines/pr95616-5.C: New test.
* g++.dg/coroutines/pr95616-6.C: New test.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/95616] [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed
2020-06-09 18:51 [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed lewissbaker.opensource at gmail dot com
` (3 preceding siblings ...)
2021-03-05 16:59 ` cvs-commit at gcc dot gnu.org
@ 2021-03-22 22:04 ` cvs-commit at gcc dot gnu.org
2021-03-24 12:45 ` iains at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-03-22 22:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95616
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Iain D Sandoe
<iains@gcc.gnu.org>:
https://gcc.gnu.org/g:00f703000fea2e8384f643413b53baa66ec4ddc2
commit r10-9513-g00f703000fea2e8384f643413b53baa66ec4ddc2
Author: Iain Sandoe <iain@sandoe.co.uk>
Date: Mon Feb 15 17:11:31 2021 +0000
coroutines : Do not accept throwing final await expressions [PR95616].
From the PR:
The wording of [dcl.fct.def.coroutine]/15 states:
* The expression co_await promise.final_suspend() shall not be
potentially-throwing ([except.spec]).
See http://eel.is/c++draft/dcl.fct.def.coroutine#15
and http://eel.is/c++draft/except.spec#6
ie. all of the following must be declared noexcept (if they form part of
the await-expression):
- promise_type::final_suspend()
- finalSuspendObj.operator co_await()
- finalSuspendAwaiter.await_ready()
- finalSuspendAwaiter.await_suspend()
- finalSuspendAwaiter.await_resume()
- finalSuspedObj destructor
- finalSuspendAwaiter destructor
This implements the checks for these cases and rejects such code with
a diagnostic if exceptions are enabled.
Backported from 9ee91079fd5879cba046e452ab5593372166b2ab and
4e252e23d34932f13f39cc6544bf5c9379fa2a87
gcc/cp/ChangeLog:
PR c++/95616
* coroutines.cc (coro_diagnose_throwing_fn): New helper.
(coro_diagnose_throwing_final_aw_expr): New helper.
(build_co_await): Diagnose throwing final await expression
components. Look through NOP_EXPRs inbuild_special_member_call
return value to find the CALL_EXPR. Simplify.
(build_init_or_final_await): Diagnose a throwing promise
final_suspend() call.
gcc/testsuite/ChangeLog:
PR c++/95616
* g++.dg/coroutines/pr95616-0-no-exceptions.C: New test.
* g++.dg/coroutines/pr95616-0.C: New test.
* g++.dg/coroutines/pr95616-1-no-exceptions.C: New test.
* g++.dg/coroutines/pr95616-1.C: New test.
* g++.dg/coroutines/pr95616-2.C: New test.
* g++.dg/coroutines/pr95616-3-no-exceptions.C: New test.
* g++.dg/coroutines/pr95616-3.C: New test.
* g++.dg/coroutines/pr95616-4.C: New test.
* g++.dg/coroutines/pr95616-5.C: New test.
* g++.dg/coroutines/pr95616-6.C: New test.
Co-authored-by: Jakub Jelinek <jakub@redhat.com>
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/95616] [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed
2020-06-09 18:51 [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed lewissbaker.opensource at gmail dot com
` (4 preceding siblings ...)
2021-03-22 22:04 ` cvs-commit at gcc dot gnu.org
@ 2021-03-24 12:45 ` iains at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: iains at gcc dot gnu.org @ 2021-03-24 12:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95616
Iain Sandoe <iains at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #6 from Iain Sandoe <iains at gcc dot gnu.org> ---
fixed for master and 10.3.
^ permalink raw reply [flat|nested] 7+ messages in thread
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2020-06-09 18:51 [Bug c++/95616] New: [coroutines] coroutines with potentially-throwing 'co_await promise.final_suspend()' expressions should be ill-formed lewissbaker.opensource at gmail dot com
2020-06-09 19:00 ` [Bug c++/95616] " iains at gcc dot gnu.org
2020-07-23 6:52 ` rguenth at gcc dot gnu.org
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